1. Field of the Invention
The present invention relates to a dialyzing apparatus which can automatically control a water-remove rate so as to efficiently remove water from blood of a patient, without causing an abrupt blood-pressure decrease in the patient.
2. Related Art Statement
There is known a dialyzing apparatus which artificially removes, by utilizing osmotic-pressure difference or ultrafiltration, urea, uric acid, or creatinine, together with water, from blood of a patient. When the dialyzing apparatus is used, a patient whose blood circulates through the apparatus, and a doctor who observes the patient cannot move away from the apparatus, for at least several hours. Therefore, it is desired to increase the water-remove rate and thereby quickly finish the dialysis operation. However, if the water-remove rate is too high, the patient may fall in a shock. To avoid this, an appropriate water-remove rate is manually set so as to allow a target water amount to be removed for a dialysis duration of from 4 to 5 hours, in view of a standard body weight and a measured body weight of the patient and a water-remove efficiency of a dialyzer, and the water-remove rate is adjusted depending upon a specific condition of the patient. The water-remove rate is defined as an amount of fluid that permeates per unit time from the blood of the patient into the dialyzing fluid present in the dialyzer through the dialysis membrane, and the fluid amount can be changed by changing a pressure difference over the dialysis membrane, e.g., changing a rotation speed of a negative-pressure pump which produces the pressure difference over the dialysis membrane.
However, the above-described adjustment of the water-remove rate needs a skillful medical specialist, such as a doctor, who can adjust the water-remove rate depending upon the specific condition of the patient. Thus, a relatively large number of medical specialists are needed as compared with a number of dialyzing apparatuses used, or a number of patients observed. However, since there is shortage of those medical specialists, the number of dialyzing apparatuses used cannot be easily increased, and each dialysis operation costs high.